Wave Energy Array WaveGrid Deep Dive: How Portugal's Coast Turns Atlantic Waves into Stable Electricity

Wave Energy Array WaveGrid Deep Dive: How Portugal's Coast Turns Atlantic Waves into Stable Electricity

Oceans cover 71% of Earth's surface, and the energy contained in waves is estimated to be more than twice the global electricity demand. Yet wave energy has failed to achieve commercial breakthrough for decades — because the ocean environment is extreme. While wave power density is considerable, the direction, frequency, and height constantly change, posing severe challenges to the reliability and lifespan of generating equipment.

Portuguese energy company Energy Waves' (EW) WaveGrid project is changing this situation. On March 10, 2029, WaveGrid completed its 50MW construction phase off the coast of Peniche, Portugal, comprising 200 WaveStar floater wave energy converters forming an array connected to an onshore substation via submarine cables.

Each WaveStar converter consists of an 8-meter-diameter floater, an arm connecting to a seabed foundation, and a hydraulic drive system. The floater moves up and down with waves, driving hydraulic cylinders to pressurize seawater to 400 atmospheres, with the high-pressure seawater driving turbine generators.

EW Engineering Director Rui Costa explained the elegance of the array design: "A single converter's power output fluctuates wildly with waves — going from 0 to 500kW within a minute. But when 200 devices form an array, phase differences between waves at different locations compress overall array output fluctuations to within plus or minus 15%. That's WaveGrid's core technology — converting intermittent energy into quasi-stable power through array effects."

WaveGrid's 50MW array is expected to generate approximately 170GWh annually, enough for about 40,000 Portuguese households. The levelized cost of electricity is approximately EUR 0.08/kWh, already approaching onshore wind costs in the country. The Portuguese government has awarded EW a 20-year Contract for Difference (CfD) guaranteeing a purchase price of EUR 0.09/kWh.

IEA ocean energy head Matthew Hanton said: "WaveGrid's array approach is the most promising technology route in wave energy in recent years. If the 50MW phase operates successfully, scaling to 200MW or even 500MW is engineering-feasible."

However, environmental organizations have raised concerns about the ecological impact of large-scale wave energy arrays. WWF ocean program head Luisa Rodriguez noted: "Wave energy converters alter nearshore hydrodynamic environments and may affect marine species migration routes and benthic ecosystems."